Typical cameras have limited depth of field (depth of focus). The depth of field depends on camera's aperture, where smaller aperture results in a relatively larger depth of field (e.g., a pinhole camera provides infinite depth of field). However, large aperture and large depth of field are both simultaneously desirable. One general approach to this problem is ‘wavefront coding’, which provides an image with an extended depth of field (EDoF). Within this basic approach, it is desirable to further extend the depth of field of lens systems to improve camera performance.